‘Humanised’ mice speak volumes about why we talk

London, May 30 (IANS) Mice carrying a ‘humanised version’ of a gene believed to influence speech and language may not actually talk, but they say a lot about our evolutionary past, according to a study. “In the last decade or so, we have come to realize that the mouse is really similar to humans,” said Wolfgang Enard of the Max-Planck Institute for Evolutionary Anthropology.

“With this study, we get the first glimpse that mice can be used to study not only diseases, but also our own history,” he said.

One important difference between humans and chimpanzees they have studied are two amino acid substitutions in FOXP2.

Those changes became fixed after the human lineage split from chimpanzees and earlier studies have yielded evidence that the gene underwent positive selection.

“Changes in FOXP2 occurred over the course of human evolution and are the best candidates for genetic changes that might explain why we can speak,” Enard said. “The challenge is to study it functionally.”

For obvious reasons, the genetic studies needed to sort that out can’t be completed in humans or chimpanzees, he said. In the new study, the researchers introduced those substitutions into the FOXP2 gene of mice.

They note that the mouse version of the gene is essentially identical to that of the chimps, making it a reasonable model for the ancestral human version.

Mice with the human FOXP2 show changes in brain circuits that have previously been linked to human speech, the new research shows, said a Max-Planck release.

Those differences offer a window into the evolution of speech and language capacity in the human brain. They said it will now be important to further explore the mechanistic basis of the gene’s effects and their possible relationship to characteristics that differ between humans and apes.